Please help me, I need all of the answers besides number 8. I'll give Brainliest, 5 star, and a like. This is for nidterm, so please, please help me out.

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.